Hyper-V Replication Avoids Downtime

A server’s failure can bring operations to a sudden halt. If your website goes offline, that can stop sales and make your business look unreliable. If an internal database fails, employees can find themselves stuck with nothing to do.

A failover server can protect against this scenario and keep you running. It’s a twin of the primary server, ready to take up the job when it’s needed with almost no downtime. Having a computer dedicated just to standing by isn’t always the most economical approach for a small business, though. If all you need is a virtual machine on shared hardware, the failover can also be a virtual machine.

Microsoft’s Hyper-V Replica feature makes this possible. With Windows Server 2012 or later, creating a replica VM is easy. With Server 2012 R2, you can have Hyper-V copy the primary to the secondary every thirty seconds, five minutes, or fifteen minutes. The initial replication won’t happen that fast, of course, but after that only changed data gets copied. The data can optionally be encrypted; you should always enable this option if the copy goes through the Internet.

The hosting machines can reside in different geographic locations, so that one disaster won’t take them both out. One could be on the company’s premises and another in a data center, or they could be in different offices. If a company has multiple servers, each machine can be the primary host for some of them and the secondary for others. In a failover situation, one of the machines takes up the whole load until it’s possible to restore or replace the other. Each copy is completely independent of the others.

Hyper-V isn’t limited to a single replica. For the best guarantee of uptime, each virtual machine can have several copies and each physical server can host several of them. In this case, multiple servers will share the workload when one of them goes down.